This invention relates to apparatus for loading flat workpieces and for sorting and transporting finished parts cut from a flat workpiece using selectively targetable suction grip control.
Suction grip loading systems for transporting flat workpieces such as sheet metal to a punch press or similar processing machine and/or for depositing them on a machine tool platform have been known as seen in German Patent No. 3637567. They combine individual suction grippers into a frame-mounted suction grip array. Retrieval of the finished parts from the residual sheet is performed manually.
German Offenlegungschift 3234216 describes a method for the unloading of processing machines in which the base position of the workpiece holder is shifted relative to the pick-up unit so that all suction grips line up with surfaces of the respective finished parts. Where larger batches of identical parts are involved, it is necessary, prior to the operating cycle, to manually arrange the individual suction grips within the suction grip array so that, for the unloading steps they are aligned in the correct position.
German Patent 3 628 381, describes a suction grip array in which the suction grips are arranged in parallel rows attached to tubular vacuum lines. By valves each vacuum line can be individually controlled, allowing the suction grip array to be adjusted in terms of its width or in adaptation to the weight of the workpiece. However, no provision is made for the selective retrieval of finished parts and, if it were made, it would be possible only by row but not within a row.
Similar functionality is offered by a device for holding a printed circuit board as described in German Patent 19646186. In this case, the suction grip array is subdivided by a template mounted in front of the vacuum passages so that only those suction grips are activated that make contact with smooth finished part surfaces. A changeover to another product requires a rearrangement of the grips and/or a change of the template. Unloading with a change in the cutting program from one workpiece to another corresponding to the finished-part distribution is possible only with a substantial manual effort.
It has also been possible to selectively control and activate individual suction grips in cases involving a small number of suction grips. The smaller the size of the finished parts punched from a large sheet of material, the smaller and more numerous the suction grips must be, making this individual control approach uneconomical, complex and excessively material intensive.
It is the objective and purpose of this invention to provide a novel loading system permitting selectively targetable, simple, easily manageable suction grip control within an array of a large number of suction grips, allowing the transport and sorting of both large workpieces and small finished parts, designed to operate in easily manageable fashion and cost effectively by virtue of low material requirements, and employing a modular control system that permits easy interchanging of the control elements.